The temperature control of inking rollers in printing machine inking units has in the past been achieved in various forms. German Pat. No. 2,658,380, for example, discloses a temperature-controlled inking roller in which at least one displacement member is disposed inside the inking roller. The unoccupied cross-section of the inking roller is divided up into two concentric annular gaps by a partition in the form of a casing having good thermal conductivity. The annular gaps have a temperature-control medium flowing therethrough at high speed in counter-current fashion. The problem with this arrangement is to devise an inking roller so that the ink temperatures remain largely constant even when the printing machine is not in use, thereby minimizing any difference in the temperature of the film of ink over the roller length.
U.S. Pat. No. 2,555,410 attempts a different method for maintaining uniform temperature. In this case, the temperature-control medium flows radially from a distributor tube disposed on the inking roller center line into a developing counter-current. The temperature-control medium flows irregularly from bores which are distributed uniformly over the length of the distributor tube and emerges into the main part of the hollow roller. However, it is still not possible to achieve a constant temperature over the roller length, even with this method.